mirrors/gcc
1
0
Fork 0
mirror of https://gcc.gnu.org/git/gcc.git synced 2024-11-23 02:44:18 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

doc/cpp: Document __has_include_next

Browse Source 
While hacking on an unrelated change, I noticed that __has_include_next
hasn't been documented at all.  This patch adds it to the __has_include
manual node.

gcc/ChangeLog:

	* doc/cpp.texi (__has_include): Document __has_include_next
	also.
	(Conditional Syntax): Mention __has_include_next in the
	description for the __has_include menu entry.
This commit is contained in:
Arsen Arsenović 2024-10-18 23:14:58 +02:00 committed by Arsen Arsenović
parent 338d687e2a
commit ffeee625c5
No known key found for this signature in database
GPG Key ID: 52C294301EA2C493
1 changed files with 22 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
gcc/doc/cpp.texi
View File

@ -3204,7 +3204,8 @@ directive}: @samp{#if}, @samp{#ifdef} or @samp{#ifndef}.
* @code{__has_builtin}::
* @code{__has_feature}::
* @code{__has_extension}::
* @code{__has_include}::
* @code{__has_include}:: @code{__has_include} and
@code{__has_include_next}
* @code{__has_embed}::
@end menu
@ -3607,22 +3608,27 @@ details of which identifiers are accepted by these function-like macros, see
the Clang documentation}}.
@node @code{__has_include}
@subsection @code{__has_include}
@subsection @code{__has_include}, @code{__has_include_next}
@cindex @code{__has_include}
@cindex @code{__has_include_next}
The special operator @code{__has_include (@var{operand})} may be used in
@samp{#if} and @samp{#elif} expressions to test whether the header referenced
by its @var{operand} can be included using the @samp{#include} directive. Using
the operator in other contexts is not valid. The @var{operand} takes
the same form as the file in the @samp{#include} directive (@pxref{Include
Syntax}) and evaluates to a nonzero value if the header can be included and
to zero otherwise. Note that that the ability to include a header doesn't
imply that the header doesn't contain invalid constructs or @samp{#error}
directives that would cause the preprocessor to fail.
The special operators @code{__has_include (@var{operand})} and
@code{__has_include_next (@var{operand})} may be used in @samp{#if} and
@samp{#elif} expressions to test whether the header referenced by their
@var{operand} can be included using the @samp{#include} and
@samp{#include_next} directive, respectively. Using the operators in
other contexts is not valid. The @var{operand} takes the same form as
the file in the @samp{#include} and @samp{#include_next} directives
respectively (@pxref{Include Syntax}) and the operators evaluate to a
nonzero value if the header can be included and to zero otherwise. Note
that that the ability to include a header doesn't imply that the header
doesn't contain invalid constructs or @samp{#error} directives that
would cause the preprocessor to fail.
The @code{__has_include} operator by itself, without any @var{operand} or
parentheses, acts as a predefined macro so that support for it can be tested
in portable code. Thus, the recommended use of the operator is as follows:
The @code{__has_include} and @code{__has_include_next} operators by
themselves, without any @var{operand} or parentheses, act as
predefined macros so that support for them can be tested in portable
code. Thus, the recommended use of the operators is as follows:
@smallexample
#if defined __has_include
@ -3645,6 +3651,8 @@ but not with others that don't.
#endif
@end smallexample
The same holds for @code{__has_include_next}.
@node @code{__has_embed}
@subsection @code{__has_embed}
@cindex @code{__has_embed}